Originally, astrology foretells the future or fortune from the positions of the sun, the moon and various planets in the solar system, and an astrological calendar is generally used for calculating angles representing their positions and directions in the heavenly bodies. However, no mechanism has yet been available which can easily determine the positions of various heavenly bodies at a necessary point of time without relying upon the astrological calendar. Incidentally, the term "astrological calendar" means a kind of table which describes the positions of various heavenly bodies relating to the year, month, day and time by numeric figures and which is very complicated to use. In astrology using the astrological calendar, the positions of the heavenly bodies are based upon the noon as the time reference. Therefore, if one wishes to know the present positions, he must make calculation to correct the time. Particularly the moon which rapidly moves in a heavenly sphere has not much been utilized in astrology because the correction is troublesome, although it is known that the moon exerts great influence upon everyday's fortunes.